Display screen or portion thereof with a graphical user interface of an electronic device



The sole FIGURE is a front view of a display screen or portion thereof with a graphical user interface of an electronic device, showing our new design.

In the FIGURE, the outermost broken lines illustrate a display screen or portion thereof and form no part of the claimed design. The remaining broken lines illustrate portions of the graphical user interface that form no part of the claimed design. 

CLAIM The ornamental design for a display screen or portion thereof with a graphical user interface of an electronic device, as shown and described. 